Oil starts with saltwater algae, which is highly renewable.. Growing genetically engineered super algae on the open ocean seems like an obvious contender for a replacement, with the added benefit it forms a CO2 closed loop. Likely the military will fund the research that cracks this nut. Any legacy oil still left in the ground might become worthless overnight, so now is the time to drill baby drill!
I firmly believe God put enough oil here for us to use as “compressed sunlight” until He decides to come back.
I think cost still leaves this as a non-option for now.
Oil has the benefit of the same processing already completed.